Patent GB-1142928-A (GB)
Title: An automatic system for controlling the angular position of the headlights of a vehicle
IPC: B60Q1/105
Filed: 1967-09-20
Abstract: 1,142,928. Controlling vehicle headlamps. SOC. ANON. D.B.A. 20 Sept., 1967 [4 Oct., 1966; 16 Dec., 1966], No. 42868/67. Heading F4R. [Also in Division F1] A system for controlling the inclination of vehicle headlamps in accordance with the trim of the vehicle body comprises an actuator 25 operatively connected to the headlamps and having at least one piston movable by fluid pressure between two stable positions in each of which it has a different predetermined effective area. The fluid pressure is controlled by one or more assemblies 10, 10a connected between the vehicle body and its suspension members or axles. In the embodiment shown, the actuator comprises a casing 34 and a cover 54 between which is held an elastomeric diaphragm 60, one side of the diaphragm defining a chamber 58 and the other side engaging a first piston 62, which abuts a control rod 26, and a second piston 64 loaded by a spring 72. The headlamps 30 are biased towards their normal positions by springs 66a and are adapted to be tilted by levers 91 mounted on a shaft 92 which also carries a cam 90 abutting the end of rod 26. The pressure control assembly 10 comprises a rigid bellshaped easing 16 mounted on the vehicle body and closed by an elastomeric diaphragm 18, and a knob 12 connected to a suspension member or axle and adapted to urge the diaphragm into the casing and thereby drive fluid through a conduit 24 and restricted orifice 44 into the chamber 58. In operation, when the vehicle body tilts, the pressure in chamber 58 increases until it reaches a first predetermined value sufficient to overcome the force exerted by the springs 66a and the piston 62 then begins to move away from the cover 54. As soon as this movement begins the portion of the diaphragm 60 between the periphery of the chamber 58 and the edge of the piston 64 lifts away from the cover 54 and the effective area of the piston 62 increases so that it snaps into abutment with the piston 64. The piston 62 will remain in this position until the pressure drops to a second predetermined value lower than the first value. If, however, the pressure increases to a third predetermined value greater than the first value and sufficient to overcome the force of the spring 72 the pistons 62, 64 will both snap over into abutment with a shoulder 74 on the easing 34 and will remain in this position until the pressure drops to a fourth predetermined value lower than the third value but greater than the first value. Further pistons may be provided to operate in a similar manner in series with the pistons 62, 64. A second pressure control assembly 10a may be mounted between the vehicle body and the other axle to control the fluid pressure in the chamber 78 on the opposite side of the pistons. The movement of the headlamps is then determined by the movement of the vehicle body relative to both axles. In one modification (Fig. 2, not shown), the control rod (26) is connected directly to the headlamps and a spring (66) to load the piston (62) is provided inside the actuator (25). In a further modification (Fig. 4, not shown), the control rod is connected to the headlamps by an hydraulic linkage.